Multiple focal contact lens

ABSTRACT

A contact lens construction suitable for use by individuals ordinarily requiring a bifocal prescription. The lens includes a light transmitting area interrupted by spaced-apart opaque portions. Continuous focal characteristics are achieved by utilizing light transmitting portions for providing vision requirements and for achieving a sufficient peripheral field, adequate illumination, and normal centering. A distance vision correction is provided in a centrally located lens area.

United States Patent 1191 Wesley Feb. 26, 1974 MULTIPLE FOCAL CONTACTLENS [75] Inventor: Newton K. Wesley, Chicago, Ill. [73] Assignee:Wesley-Jessen Inc., Chicago, Ill.

22 Filed: May 12, 1972 [21] Appl. No.: 252,758

Related U.S. Application Data [63] Continuation of Ser. No. 536, Jan. 5,1970, abandoned, which is a continuation-in-part of Ser. No. 632,398,April 20, 1967, abandoned.

[52] U.S. Cl 351/161, 351/160, 351/46 [51] Int. Cl G026 7/04 [58] Fieldof Search 351/160, 161, 46

[56] References Cited UNITED STATES PATENTS 3,507,566 4/1970 Knapp351/160 564,518 7/1896 Heilborn 351/46 1,206,132 11/1916 Otte 1,959,9155/1934 Guthrie... 2,129,305 9/1938 Feinbloom 351/162 FOREIGN PATENTS ORAPPLICATIONS 167,273 12/1950 Austria 351/160 369,993 12/1906 France351/46 4/1966 Great Britain 351/161 OTHER PUBLICATIONS Sefcheck, Articlein Contacto Vol. 11, No. 4, Dec. 1967, pgs. 56-59.

Mazow, Article in Contacto Vol. 2, No. 5, Sept. 1958, pgs. 128, 130&131.

Precision-Cosmet Digest Vol. 2 N0. 8 March 1962 pgs.1-6 Copy in 351/161.

Freeman, Article in American Journal of Optometry & Archives Vol. 29,No. 7, July 1952, pgs. 347-352.

Primary Examiner-David H. Rubin Attorney, Agent, or FirmPennie & Edmonds[57] ABSTRACT A contact lens construction suitable for use byindividuals ordinarily requiring a bifocal prescription. The lensincludes a light transmitting area interrupted by spaced-apart opaqueportions. Continuous focal characteristics are achieved by utilizinglight transmitting portions for providing vision requirements and forachieving a sufficient peripheral field, adequate illumination, andnormal centering. A distance vision correction is provided in acentrally located lens area.

2 Claims, 10 Drawing Figures PMmnnrsazsmm sum 2 [IF 2 PEG 5 MULTIPLEFOCAL CONTACT LENS This application is a continuation of applicationSer. No. 536 filed Jan. 5, 1970, now abandoned, which is acontinuation-in-part of application Ser. No. 632,398, filed Apr. 20,1967, now abandoned.

This invention relates to contact lenses and is particularly directed toa contact lens having continuous focal characteristics.

Bifocal contact lenses have previously been produced. Such lensesgenerally follow the design of bifocal lenses employed in conventionaleye glasses in that a more or less definite line of demarcation isprovided in the bifocal lenses. The wearer of the lenses must lookthrough one portion of the lens for achieving distance vision andthrough another portion of the lens for achieving close vision.

In the case of conventional eye glasses, the wearer can generallyaccommodate to bifocal lenses without undue difficulty. Usually, thewearer will look straight ahead through an upper portion of the lens fordistance vision and will lower his eyes for looking through the lowerportion of the lenses for close vision.

Bifocal contact lenses have been designed for use in substantially thesame manner. A much more difficult problem is encountered, however, withrespect to training the wearer to adjust for distance and close vision.Since the lens rides directly on the eye, there is obviously a verylimited area for eye movement whereby one portion of the lens can beemployed in preference to another portion. Furthermore, any shifting ofthe lens position on the eye will require a corresponding adjustment ofthe wearer further complicating the use of the lenses.

Pinhole contact lenses have been proposed, for example, as discussed inan article entitled Bifocal Contact LensesT published in thePrecision-Cosmet Di- It is a general object of the instant invention toprovide a contact lens construction which will provide continuous focalcharacteristics while eliminating many of the difficulties encounteredin the use of previously designed bifocal contact lenses.

It is a further object of the instant invention to provide a continuousfocal lens of the type described which can be manufactured and fittedwithout undue difficulty thereby enabling prescription of the lenses ata relatively low cost.

lt is a still further object of this invention to provide a continuousfocal lens utilizing in part a pinhole principle along with importantadditional features which eliminate difficulties previously experiencedand which thus provide a practical continuous focal lens.

It is a still further object of this invention to provide a contact lensof the type described which can be readily manufactured as cosmeticlens.

These and other objects of this invention will appear hereinafter andfor purposes of illustration, but not of limitation, specificembodiments of the invention are shown in the accompanying drawings inwhich:

FIG. 1 is a cross-sectional view of a lens of the type produced inaccordance with the features ofthe instant invention; and,

FIGS. 2 through 10 illustrate a variety of designs for pupil areas oflenses adapted to be employed in accordance with the concepts of thisinvention.

The lens of the instant invention may comprise a conventionalconstruction, for example of the type disclosed in Touhy US. Pat. No.2,510,438. Such lenses comprise so-called corneal lens constructions andhave, generally speaking, a pupil area and a surrounding iris area. Itwill be understood that the invention is also applicable to contact lensdesigns other than the corneal type.

Pupil and iris areas are not precisely defined clue to the fact that thepupil size changes with light conditions and because of different eyecharacteristics among patients. Accordingly, where reference is made toan iris area and a pupil area of the lens in the specification andclaims, this should be understood to mean the usual areas of the lenswhich are superimposed over the pupil and surrounding iris under normallighting conditions, and these are well known to experiencedpractitioners.

The specific contact lens of this invention defines a concave-convexshape with the concave surface being adapted to adhere to and float onthe cornea. The concave surface has a curvature which substantiallyconforms to the cornea; however, in this connection, precise conformingof the respective curvatures is not achieved. This is partly due topractical limitations in manufacturing; however, deliberate variationsare also provided for specific reasons. Thus, a definite deviation isprovided near the center of the lens and cornea to insure the presenceof a tear layer. Other deviations, particularly around the periphery areprovided, for example, as discussed in the aforementioned Touhy patent.

In accordance with the principles of this invention, the pupil area ofthe lens comprises a centrally located, light transmitting opening. Thisopening is surrounded by an opaque region which occupies a portion ofthe pupil area and which may extend into the surrounding iris area. Thisopaque region is interrupted by light transmitting openings located inthe pupil area. Thus, light is passed through the lens in the centrallylocated area as well as through the light transmitting openings whichinterrupt the opaque region. A limitation is placed on the extent of theopaque region so that light is also passed through the lens beyond theouter limit of the opauqe regions.

The centrally located light transmitting opening is provided with anoptical correction in accordance with the distance vision requirementsof the wearer. The lens which results from this combination has beenfound to provide the necessary distance vision requirements since thewearer automatically will employ the centrally located lighttransmitting opening when viewing objects at a distance. Surprisingly,the combination described also provides for close vision even where nospecific correction is made outside the area of the centrally locatedpupil opening. Thus, the distance correction may extend across the lensor no correction at all may be employed beyond the centrally locatedopening. Nevertheless, the light transmitting interruptions in theopaque region, in combination with the central opening, have been foundto provide for close vision, adequate peripheral field, and satisfactoryillumination, while the outer areas of the lens beyond the limits of theopaque region cooperate with the light transmitting interruptions toprevent loss of vision upon decentering of the lens.

The lens of this invention differs from a typical bifocal lens since abifocal employs two basically different optical corrections toaccommodate distance and close vision. As pointed out, the lens of thisinvention provides a continuous focal arrangement since the user isaware of no demarcation for near and distance vision. The lens makes noprovision for any correction other than the distance correction with thecentral opening and other light transmitting interruptions in the opauqeregions providing for close vision. The invention also eliminatesproblems associated with pin hole bifocal lenses. Thus, peripheralvision is not impaired, completely adequate illumination is provided,and fitting methods requiring normal centering can be used since visionis still accomplished if the lens is decentered.

The lens construction illustrated in FIG. 1 comprises an area 12 whichconsists of the pupil area under normal conditions and a surroundingiris area 14. In accordance with the concepts of this invention, thepupil area is provided with opaque areas and interrupting openings whichprovide for transmission of light.

FIG. 2 illustrates one practical embodiment of the invention. The lensillustrated consists of a centrally located light transmitting opening13 in the pupil area 12. This opening is surrounded by opaque regions 15which are interrupted at 16 to provide light transmitting slits. Theregions 15 define semi-circular cut-out areas 19 which, if the lens isnot centered, may act as secondary pinhole openings.

In a typical case, the lens shown in FIG. 2 may have an outer diameterof 9 mm with the outer diameter of the opaque region 15 being 4.5 mm.The central opening 13 will have a diameter of 1.5 mm and the slits 16have a length of 1.5 mm and a width of 0.4 mm.

The dimensions of contact lenses vary in accordance with the needs of aparticular patient. It has been found, however, that for the averagepatient the centrally located opening in the pupil area, if circular,should not have a diameter in excess of 2 mm and preferably not lessthan 1 mm whereby the area of the light transmitting opening will bebetween about 0.8 mm and 3.14 mm. For the case ofa patient requiring ahigh add, the diameter may go as low as 0.5 mm. The opaque areasurrounding the light transmitting central opening should have a widthof at least 0.5 mm in all directions with the exception of thoseportions interrupted by the additional light transmitting openings. Thisopaque area should extend for 1.0 mm but not beyond about 3.00 mm whenmeasured from the center of the pupil area 12, to provide adequateillumination, and to permit distance vision if the lens decenters. Withthis limitation, the opaque region will be about the same as the pupildiameter of the average person under normal lighting conditions (about10 foot candles). The openings 16 should have a minimum dimension in anydirection between about 0.2 mm and 0.7 mm.

In the use of the lenses illustrated, the wearer places a lens in eacheye in conventional fashion. Proper correction for a nearsightedcondition can be provided at least in the region 13 of the lens withoutdifficulty. Surprisingly, the provision of the central opening 13 alongwith the openings 16 interrupting the opaque areas 15 provides for closevision, the peripheral field and illumination. This can be accomplishedwithout a prescribed optical correction in the area of the lens outsidethe central opening 13, however, a prescription for distance, forpractical reasons, is usually ground across the entire lens.

Lenses of the type contemplated may include opaque portions of variouscolors to provide a desired cosmetic effect. Where reference is made toopaque portions, it will be understood that semi-opaque characteristicsof at least 50 percent reduction in light transmission are contemplatedsince the primary purpose is to eliminate a significant lighttransmission except through the openings 16.

Coloring of the pupil and also the iris areas can be accomplished inaccordance with conventional techniques wherein pigments are included inthe lens during manufacture, or wherein opaque materials are painted onthe lens. The most natural cosmetic effect can be accomplished by usingopaque regions 15 which are black (however, any color which cuts out atleast 50 percent of the light, may be employed) and by limiting thedimensions of these opaque regions to the apparent size of the pupilunder natural light conditions. A blue, green, brown or other color,preferably of greater light transmitting characteristics, could then beincorporated in the surrounding iris area; however, this area is usuallyleft clear to provide adequate illumination.

In the actual prescription of continuous focal lenses, the particularvisual characteristics of the individual being fitted are naturallyconsidered. Such characteristics vary extensively, and a lens designsuitable for one individual may not be too suitable for another.Accordingly, a variety of different designs for lenses embodying theconcepts of this invention are contemplated. It has been found, however,that with the exception illustrated in FIG. 10, suitable lenses are notinterrupted by opaque areas between the central opening and additionalopenings. Thus, the advantages of the invention are not achieved wherethe slits 16 are extended from the outer edge of the opaque region butstop a significant distance short of the central opening 13.

The cut-outs 19 provide a desirable arrangement for increasing lighttransmission and act as a secondary pupil if not centered whichincreases the tolerance as far as positioning of the lens is concerned.There are still sufficient opaque areas to maintain the benefit of thecombination of opaque regions and slits, however, the cut-outs are not arequirement in all cases. FIG. 3 illustrates a modified form of theinvention wherein the opaque regions 17 are in the form of individualpieshaped segments without the semi-circular cut-outs 19 formed in eachsegment.

FIGS. 4 through 10 illustrate a variety of other lens designs which arecharacterized by the features of this invention. In FIG. 4, eightsegments 15 are employed instead of six. FIGS. 5, 6 and 7 illustratearrangements involving the use of slits in different patterns. Crossarrangements are provided by the slits 22 of FIG. 5, the slits 24illustrated in FIG. 6, and slits 25 of FIG. 7. The design shown in FIG.8 includes rectangular opaque areas 28, and it will be appreciated thatother configurations for these opaque areas will be equally suitable. InFIG. 9, the opaque areas 30 are formed by means of semi-circularcut-outs 32 which are formed closely tangent to the central opening 13.The semicircular configuration provides a desirable means forsupplementing the pinhole opening 13 when the lenses is decentered.

It will be apparent that other designs for the narrow slits or otherlight transmitting openings could be utilized, and one experienced infitting such lenses could determine the most likely configuration bystudying the eye characteristics. It is anticipated, however, that thebest designs will be determined through the use of means permittingtesting of a patient with the respective configurations.

In FIG. 10, the opaque areas are provided by means of concentric rings34, 36 and 38 which are interrupted by annular light transmittingopenings 40 and 42. Although with this design, the openings 40 and 42 donot intersect the central opening 13, it has been found that theadvantages of the invention can still be achieved. Thus, the lighttransmitting openings operate as one lens system and converge the lightat one point. Decentering does not eliminate vision, and adequateillumination is provided.

The various lens designs all eliminate problems characteristic ofpinhole contact lenses. Where a single pinhole is employed, anintolerable situation is encountered from the standpoint of peripheralfield capabilities and illumination. In addition, the wearer iseffectively blind when the lens is decentered due to blinking or for anyother reason. Where attempts have been i made to solve this by providingmultiple pinholes, diplopia (double vision) will occur with two pinholesand polyopia (multiple vision) will occur with multiple pinholes.

The simplicity of the arrangements described when compared withconventional bifocal lenses will be apparent. Techniques employed in thepreparation of cosmetic lenses can be readily adapted for thepreparation of the continuous focal lenses of this invention. The lensesdo not require any special training for the wearer since the wearer neednot hunt for bifocal segments when shifting to a different view. Thenatural reading position of the head can be used.

The lenses can be designed whereby the particular visual condition of aparticular wearer can be accommodated. It is also important to note thatthe lenses will have a natural appearance since the lenses can becolored without difficulty. In this respect, different eye colors can beprescribed where this is desired for cosmetic reasons.

An additional major advantage of the lenses relates to the ease offitting. In many cases, conventional lenses, particularly bifocals, areextremely difficult to fit since shifting on the eye is necessary forproper vision. It has been found that fitting is not nearly as criticalwith continuous focal lenses of the type contemplated by this inventionsince only normal centering is necessary.

lt will be understood that various changes and modifications may be madein the above described lenses which provide the characteristics of thisinvention.

That which is claimed is:

1. In a contact lens structure having a concaveconvex shape with theconcave surface being adapted to adhere to and float on the cornea andhaving a curvature substantially conforming to the cornea, at least thatportion of the lens designed to be located over the pupil of the wearerwhen the lens is positioned on the eye being prescription ground toprovide a distance vision correction for the wearer, an opaque regionlocated in the central portion of the lens and defining an essentiallycircular pattern, the diameter of the opaque region being at leastsufficient to provide for covering of at least said portion of the lensdesigned to be located over the pupil of the wearer, and a substantiallyunrestricted light transmitting opening defined in the center of saidopaque region, the improvement comprising a plurality of lighttransmitting openings communicating with said central opening andextending outwardly from said central opening, said light transmittingopenings being in the form of narrow slits extending radially from thecentral opening to thereby provide a plurality of wedge-shaped opaqueportions, the respective junctures of the slits with said centralopening being substantially equally spaced apart whereby saidwedgeshaped portions are of substantially the same shape, and whereinthe width of said slits is substantially smaller than the diameter ofsaid central opening.

2. A construction in accordance with claim 1 wherein said slits have awidth of at least 0.05 mm.

1. In a contact lens structure having a concaveconvex shape with theconcave surface being adapted to adhere to and float on the cornea andhaving a curvature substantially conforming to the cornea, at least thatportion of the lens designed to be located over the pupil of the wearerwhen the lens is positioned on the eye being prescription ground toprovide a distance vision correction for the wearer, an opaque regionlocated in the central portion of the lens and defining an essentiallycircular pattern, the diameter of the opaque region being at leastsufficient to provide for covering of at least said portion of the lensdesigned to be located over the pupil of the wearer, and a substantiallyunrestricted light transmitting opening defined in the center of saidopaque region, the improvement comprising a plurality of lighttransmitting openings communicating with said central opening andextending outwardly from said central opening, said light transmittingopenings being in the form of narrow slits extending radially from thecentral opening to thereby provide a plurality of wedge-shaped opaqueportions, the respective junctures of the slits with said centralopening being substantially equally spaced apart whereby saidwedge-shaped portions are of substantially the same shape, and whereinthe width of said slits is substantially smaller than the diameter ofsaid central opening.
 2. A construction in accordance with claim 1wherein said slits have a width of at least 0.05 mm.